I am Welsh and this is my name.
Rh is a letter in the Welsh alphabet,a sound not used in English. Place your tongue on your palette and blow swiftly while making an r sound,followed by ee. All Welsh words have emphasis on penultimate syllables.

It's my name and I am Welsh. Rh- place your tongue behind your front teeth and swiftly blow as you make an r sound blending into ee,not used in English.Emphasis is always on the penultimate syllable in Welsh. Rhee AN on

It is most definitely not Ree-an-un Rhiannon doesn't have a U in the name so how does that work ,eh? My name is Rhiannon and nobody AT ALL says Ree-an-un because it just doesn't make sense. Google is always correct , no matter what!